Article of manufacture



v I QvWa/MM Max NBIhElTL Ninkuwfiz Patented Oct. 29, 1940 UNITED STATES PATENT OFFICE.

2,219,697 narrow or MANUFACTURE Max Nathan Nickowitz, Bridgeport, Court, as-

signor to E. I. du Pont de Nemours & Company, Wilmington, DeL, a corporation of Delaware Application September 21, 1939, Serial No. 295,961

. 2 Claims. (01.36-44) been commercially unsuccessful. The stocks or I sheet materials proposed for use in lieu of leather in such manufacture have had a number of prohibitive disadvantages.

A very desirable insole (or sole support) for this type of shoe, can be manufactured by splicing or cementing a flexible ball portion to stiff toe and/or heel portions having suitable characteristics. Heel and toe portions that are tough and stiff prevent buckling during the lasting operation and prevent the pulling through of the lasting and heel attaching nails.

This invention had for an object the preparation of an improved insole and insole material. Other objects were to devise an insole of m proved characteristics, to prepare an insole or materials that are cheaper and more readily available than leather, and to prepare an insole which could be used in the manufacture of shoes by cementing (for example,- Compo) processes.

:0 Still another object was to produce an insole which could be used in the'manufacture'of shoes by either a cementing or sewing process. A general advance in the art and other objects which will appear hereinafter were also contemplated. It has now been found that an insole having the aforementioned desirable properties and accomplishing the aforementioned objects may be prepared by laminating a rigid fiber board with a porous absorbent paper and splicing toe' and 40 heel portions of such laminated material to a flexible ball portion. v

My invention in its preferred formis illus-. tratedin the accompanying'drawing in which! Figure 1 is a bottom view representing some- 45 what diagrammatically one form of the insole of this invention, V Figure 2 is a sectionalview of the insole of Figure 1, the section being along the line 2-2 of Figure 1, Figure 3 illustrates one kind of blank from which the insole represented in Figure .1 might be cut,

Figure 4 is an enlarged sectional view' corresponding to the lower splice portion of Figure 2 55 and illustrates a modified form of the invention,

Figure 5, similarly to Figure 4, illustrates still another form of splice, and

Figure 6 is anenlarged sectional view correw sponding to the upper end of Figure 2 and illustrates the position of a. insole m .n assembled shoe.

Similarcharacters refer to similar parts throughout the drawing.

Referring to the drawing, the' insole illustrated in Figure 1 comprises a ball portion I of flexible material such as low grade leather but preferably of porous absorptivematerial such as the latex saturated paper referred to hereinafter, a toe portion 2 of stiff, tough material capable of resisting the pulling through of nails used in the lasting operation and a unitary portion constituting the shank 3 and heel l composed of the same'mat'erial as the toe portion 2.

As will be clearfrom the sectional view in Figure 2, the ball portion illustrated consists of a single thickness (laminated material can be used if desired) of material. The toe portion is laminated and comprises a layer 225 ,of tough stiif fiber board cemented by a layer of cement 221 to a porous, bibulous layer 226 of paper or the like which, as shown in the drawing is substantially thinner than the fiber board layer. The laminated toe portion is secured to the ball por-' tion by a layer of cement 228.

The shank-heel portion isfsirhilar to the toe portion and comprises a tough fiber board lamina 25 secured by a cement (usually rubber, cement) layer 2! to the bibulous layer 26. The rear (shank-heel) portion of the insole is secured to the ball portion by. a layer of cement 28 in the same manner as the toe portion.

The end edges of toughfiber-board layers are joined'to the end edges of the ball portions since it is not possible to accomplish the objects 'of this invention by'attachingthe hard layers to one side of a single sheet of the absorbent material constituting the ball portion. In such construction the hard layerswhen thin enough to give the substantially continuous surface desired for the present purpose would be too thin to give the required reinforcement to the soft, flexible ball portion used in the practice of this invention. The hard reinforcinglayer' should be as thick as possible and may practically approachthe thickness of-the ball portion. The absorbent layer of the toe and heel portions on the other hand should be quite thin and is desirably not more than 25% of the total thickness of the heel or toe portions. Whenthe hardlayers 25 and 225 are made the thickness of the ball portion and the paper or absorbent layer'of the toe and heel portions is so thin that the surfaces of the ball portions andthat of the paper toe and heel portions can be regarded as substantially continuous.

The stock from which the insole iscut is preferably manufactured in 'sheets. These sheets may vary in size so that one or a plurality of insoles may be cut therefrom. A blank suitable for the cutting of a single insole is illustrated in Figure 3. The dotted line 30 indicates the outline to be followed in cutting or stamping the other and in commercial operation they are also parallel to the edges of the blank from which they are out. By using insoles in which the two splices have parallel edges, the blanks can be economically cut in long rows from the stock without changing the alignment of the stamping die or dies relative to the splice lines.

It is not necessary to cement the toe and/or heel-shank portions to the ball portion as illustrated in Figures 1 and 2. If desired, the attachment may be'made by means of stitching, stapling or equivalent means, including various combinations of cementing, stitching and stapling. In Figure 4 one such modification is illustrated. The ball portion 4| is attached by lines of stitching 45 to the shank portion which comprises laminae 45 and 46 united by a layer of cement 41. The tough fiber board layer is shown In Figure 5 a still further modification (employing stapling) is shown. In this figure the flexible ball portion 5| is united to the shank portion by means of a single line of stapling 59 and a layer of cement 58. The layers indicated at 55, 56 and 51 correspond to the layers 25, 2G and 21, respectively, in Figure 2.

As previously indic-ated,- the sole of the shoe utilizing this invention is cemented to the insole after the insole has been nailed or otherwise attached to ,the upper portion of the shoe. The relation of the sole and insole (at the toe) is illustrated in Figure 6, wherein the insole assembly comprising a tough fiber board layer 6225 is united to a porous lamina 6226 by means of a cement layer 6221. -In this assembly the shoe sole 6 is umted to the, absortive layer 6226 by means of a layer of cement 61. Methods of joining sole and insole are well known in the art (see for example U. S. Patent 1,967,337).

The lamination of the toe and the shank-heel stock is usually carried out before the skiving and cementing of these portions to the skived flexible ball portion. It is possible to cut the various portions of the insole to shape and therecut and then finish assembling, but in commercial practice a stock sheet material is prepared and shipped to the shoe manufacturer who cuts or stamps insoles of various sizes and types therefrom. This has been found to be a more economical procedure.

The toe and shank-heel portions are ordinarily made up of two layers of material permanently laminated by means of suitable cement. In the insole illustrated in the drawing these portions "consisted of a layer of tough stiff fiber board cemented to a porous layer of paper. In some instances it may be desirable to cement an absorptive layer to both'sides of the still layer.

Even more laminae may be used for special purany stifi rigid sheet material otherwise suitable for insole construction may be used for the tough layer. In the place of the fiber board mentioned above, other absorptive material such as paper, which has been impregnated and/or coated with a resinous material to render it stiff and rigid, may be used. The chief requirement is that the stock used have suflicient rigidity and toughness to withstand the lasting operation and pulling through of the lasting and heel attaching nails. A wide range of materials are suitable for the absorptive layer. Mention may be made of sized and unsized woven fabrics, woven fabrics saturated with latex, sized. and unsized-paper, paper saturated with binders such as glue, casein, shellac, asphalt and rubber, leather skivings, split leather and the like. The preferred material is a rubber saturated paper, in which the rubber has been applied in the form of latex. Satisfactory material is also obtained by substituting rubber cement for the latex. The paper may be saturated by passing it, while dry, through a bath of rubber cement or latex, squeezing out the latex and drying. The material produced according to United States Patent 1,966,458 is especially suitable. In general any porous material capable of readily absorbing a layer of shoe. cement and having properties otherwise suitable for insole construction may be used.

The materials mentioned for the porous layer of the toe and shank-heel portions are in general suitable for the ball portion. In addition, such materials as leather, artificial leather, leather substitutes and the like may be used.

The most valuable embodiment of this invention is that in which the absorptive ball portion, and preferably also the absorptive laminae at heel and toe, consists of a latex saturated paper containing rubber sufficient to confer the required strength but insuflicient to prevent the sole absorbing the adhesives used'in shoe making. Once the sole is cemented to the shoe the internal strength is sufllcient to prevent internal fiber separation when'a strain is not upon the sole. For the present purpose the rubber in the latex impregnated paper should not usually be above 35% or below 15% and is ordinarily about 20%. A typical latex impregnated paper suitable for the present purpose is one consisting of about 43% unbleached krait pulp, 21% wood flour, 21% chrome leather, and 15% rubber. Another example of a similar porduct is one having the approximate composition of I 54% paper pulp, 7% wood flour, 7% asbestos, 17% chrome leather, and 15% rubber.

Any type of adhesive cement which will unite the plies of the laminated portions and which will unite the resultant laminated ma erial to the flexible ball portion, may be used. Rubber cements have been found to be especially suitable for these purposes. A typical cement is given in Example 1.

Example I Total 100 In attaching the sole to the insole, the standard air-drying pyroxylin cements are used. Such cements are well known to those skilled in the art and in the patent literature (see for example U. S.

aaiacev Patent 1,959,323). Specific typical examples of such compositions are given in Examples 11 and III.

The nitrocellulose in these compositions preferably has a viscosity of 20-30 seconds, as determined by the method outlined in the A. S. T. M. specifications D-301-31T formula A, and a nitrogen content of 12.30 to 12.50% as determined according to the A. S. T. M. specifications 33-301- 31T. These examples are given for purposes of illustration, and are merely representative of many pyroxylin cements suitable for use in the well known Compo processes of shoe manufacture.

As previously indicated, the character of the various parts of the insole will vary somewhat with the use to which the insole is to be put, as for example, an insole suitable for ladies evening slippers and like uses may consist of a ball portion thick and weighing 4 ounces per square foot, a toe-heel portion having an absorptive layer thick weighing 1 ounce per square foot, and a tough, stiff fiber board layer 5" thick weighing 3 ounces per square foot. Obviously the insole of footwear subject to more severe conditions would require proportionately heavier and stronger construction in some or all ofthe above component parts.

The insole of this invention makes it possible to use. paper, fiber board and like leather substi- 5 tutes in the manufacture of shoes by the so-called cement processes. The conventional shoe cements will bite in to these insoles in the time allowed for such an operation in present commercial practice in the manufacture of cement lasted shoes.

As many apparently widely difierent embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that I do not limit myself to the specific embodiments thereof except as defined in the appended claims.

I claim:

1. An insole adapted to be cemented to a shoe sole which comprises a flexible porous absorptive 20 ball portion and laminated toe and heel portions comprising at least two laminae attached to the ends of said ball portion, the laminae of both said portions being separate from said ball portion, one lamina of each of said toe and heel portions on the same side of i the insole being a layer of stiff tough material joined at an end edge to an end edge of the ball portion whereby the surfaces of said ball portion and tough layers are substantially continuous, the other of said laminae consisting of a layer of absorbent material attached to each of the tough layersat. the side of the sole opposite said surfaces, said layers of absorbent material being substantially thinner than said layers of tough material. 3

2. An insole adapted to be cemented to a shoe sole which comprises a ball portion consisting of a latex impregnated paper absorptive to shoe cement, and laminated toe and heel portions joined to the end edges of the ball portion, said laminated'portions each comprising a layer of fiber-board having attached to one face thereof a' layer of latex impregnated paper which is substantially thinner than said fiber-board layer.

MAX

NATHAN NICKOWITZ. 

